Add missed legancy lpc43xx board compatible string to fix below CHECK_DTB
warnings:
arch/arm/boot/dts/nxp/lpc/lpc4337-ciaa.dtb: /: failed to match any schema with compatible: ['ciaa,lpc4337', 'nxp,lpc4337', 'nxp,lpc4350']
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>